Electrical control system



April 1961 F. R. MARQUARDT 2,981,157

ELECTRICAL CONTROL SYSTEM Original Filed April 18, 1950 PROJECTOR SWITCHES LOWER BAR REL RELAY UPPER BARR EL 252 RELAY 324 CYGLIC 254 RATE f B TIMER 28 VOLT 255 A I 32 233525 0 R L w qrs (254a READY I INVENTOR FRANK R. MAgl/ARDT BY QBQWTZNEYS ilnited States Patent ELECTRICAL CONTROL SYSTEM Frank R.,Marquardt, Alexandria, Va.

' 4 Claims. (Cl. s9 13s (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used, by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor;

The instant application is a divisional application of Frank R. Marquardt, Serial No. 156,641, filed April 18, 1950, now Patent No. 2,972,286, and entitled Rapid Fire Gun.

The present invention relates to acontrol system and more particularly to a new and improved electrical control and firing system for a rapid fire gun. :Moreover, the invention provides an electrical firing and operational control system for automatic guns which accomplishes the loading of rounds into the firing chambers of a rotary breech, the appropriate firing of rounds so loaded to enable the counteraction of "the recoil energy of one firing by the recoil energy of a subsequent rounds into the complementary firing chambers in a rotary breach. v I

' Closing of the aforesaid ready switch also energizes the charger relay which opensthe charger circuit. included in the circuit is a gunswitch which is open when the gun is in battery position. Closing the firing switch energizes the upper gun barrel relay and establishes an electrical circuit through the uppergun barrel relay tobreak the charger circuit. The charger relay is provided with a delayed pull out of approximately fifteen milliseconds and thus when such period of time has elapsed'the charger circuit is closed by the charger relay and the charger solenoids are energized. Upon energization of the charging solenoids, charger valves (shown in the aforementioned application) allow air in a pressure tank (also shown in the aforementioned application) to enter pneumatic chargers which, in turn, push the recoiling components of the gun in an aft or a forward direction.

In response to such movement of the gun, the aforesaid gun switch is closed resulting in the lower gun barrel relay being energized and thus closing the lower barrel firing circuit and the circuit to the charger solenoidrelay. When the charger solenoid relay is enerthe two gun barrels. Moreover, as the gun enters the in-batteryv position, a pair of firing pin devices allows the aforesaid condensers to discharge through the electrical primers in the cartridge cases, aligned with'the gun barrels, thereby to fire the primers. As the two rounds are fired, the forward motion of the recoiling mass will be stopped and the recoiling mass sent aft with approximately the impulse of one round since the charger imparts approximately the same energy to the recoiling mass as the firing of one round of ammunition. Each of rotation of the firing chamber causes two projectors to be fired with the result that two rounds are loaded into the firing chambers.

The gun continues to fire two rounds each time the recoiling components enter the in-battery position until the aforesaid firing switch is opened, at which time the top gun barrel relay is released, breaking the firing circuit to the top barrel. The lower gun barrel relay by reason of the aforesaid delay allows the lower barrel firingcircuit to remain closed for a predetermined period of time, such for example, as for the gun to comgized, the electrical circuit to the charger solenoids are broken whereupon the charger solenoid 'valves are closed, cutting. 0E the supply of air to the charger pistons and v at the end of the stroke of the pistons the air is exhausted into the atmosphere. At this time the energy plete the cycle and fire the lower barrel round, thereby ending the burst with a live round in alignment with the upper barrel, a fired cartridge case in alignment with the lower barrel and a pair of live rounds loaded in the chambers adjacent to theupper and lower gun barrels.

When the aforesaid firing switch is actuated to a closed position again to fire the next burst, the upper barrel gun relay closes the firing circuit and the upper barrel condenser discharges through the electric primer in thebase of the round aligned with the upper barrel thereby firingthe round in the upper barrel and starting the second burst. The shortest burst that can be fired is two rounds, for example, one to start the burst and one to stop the burst.

When one round fails to fire during a burst, the round that did fire as the gun came into battery, will stop the gun in the same manner a normal burst is stopped by firing only thelower barrel, the only difference being that the firing switch is still closed when the gun comes to rest. When the gun remains at rest with the gun switch open, the lower barrel relay will pull-out and thus break the circuit to the charger solenoid relay to close the electrical circuit to the charger solenoids whereupon the gun goes through a charging cycle as heretofore set forth. As the gun returns to battery after the charging cycle, a pair of new rounds will be fired and the dud, if any, and empty cartridge case, having rotated through 45, will be ejected. Should the dud occur in the lower barrel after the firing switch is released to stop a burst, the forward motion of the gun would not be stopped by the firing of the lower barrel and the live round in the upper barrel would not be fired to stop the forward motion since its firing circuit is broken when the firing switch is released. The forward motion of the gun under this condition is stopped in the manner set forth in the aforementioned application.- As is clearly disclosed in that-application a transferof energy takes place while the gun is being stopped and, during'this transfer of energy, the chamber is rotated through 45 bringing two new rounds into alignment with the barrels. As the gun enters the in-battery position again, the round aligned with the lower barrel will be fired thus stopping the gun.

When two duds are encountered simultaneously in both the upper and lower barrels, the same condition prevails as when a dud occurred in the lower barrel after the firing switch is released as heretofore set forth, the only difference being that the firing switch is closed so that,

when the gun returns to the in-battery position after being buifed in the forward direction and indexed through the cams, in a manner as clearly set forth in the specification of my copending application, Serial No. 156,641, now Patent No. 2,972,286, aforementioned. Should the firing switch be released, however, when two duds occur, only the lower barrelwill fire when the gunireturns to the inbattery position, thereby stopping the gun with a live round in alignment with the upper barrel and, a fired cartridge in alignment with thelower barrel. It will be understood' that the charger only operates when one dud'occurs during a burst and the firing switch remains closed.

An object of the present invention is to provide a new and improved electrical firing system suitable for use in a rapid fire gun.

Another object of the invention is to provide an electrical controlled firing system for a rapid fire gun to enable variations in the rate of firing between bursts or during any particular burst.

Another object of the invention is to provide a fire control system for an automatic. gun wherein a larger number of rounds may be automatically fired. within a given period of time than has heretofore been possible, and inwhich the rate of a burst of rounds or during such a burst may be controlled at will by the operator.

Another object of the invention is to provide a fire control system fora rapid fire gun wherein means automatically fire the gun upon its approach to a battery position.

Another object of the invention is to provide a tire control system for a rapid fire gun wherein explosive means quickly and efficiently load rounds into a gun.

A further object of the invention is to provide anelectrical firing operational control system for automatic guns which accomplishes the loading of rounds into the firing chambers, the appropriate firing of rounds loadedin such a manner enabling the counteraction of the recoil energy of one firing by the recoil energy of a subsequent firing, and the automatic charging of the gun when at rest, and enables an adjustment of the rate of automatic fire.

Still another object of the invention is to provide an electrical firing system for an automatic gun wherein explosive means fired when the rounds are in alignment with the firing chambers of a rotary breech forceably eject the rounds into the chambers.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered with the accompanying drawing wherein:

The single figure is aview in diagramrnatical form of the electrical firing and operational control circuit constructed in accordance with the present invention.

Referring now to the drawing the electrical control and firing system is generally indicated by the reference character 250 and comprises a source of power, such for example, as a battery B connected to a motor 251 by way of conductors 326 and 321, conductor 320 having a suitable switch 253, hereafter referred to as a ready switch and also connected relays 256, 260 and 262 whereupon the battery is adapted to operate motor 251 and the aforesaid relays when the switch is actuated to a closed position. Relay 256, it will be noted, is the upper barrel relay, relay 262' being the lower barrel relay and relay 260 being the charger relay. Relay 256 is provided with a pair of mutually spaced contact arms 258 and 259, arm 253 normally engaging a pair of contacts 258a and arm 259 being normally out of engagement with a pair of contacts 259a. Relay 256 is further provided with .a contact arm 257 normally out of engagement with a pair of contacts 257a. The lower barrelrelay is provided The charger contact arm 261 normally in It will be noted that one of the contacts 258a is connected to ready switch 253 by conductor 320, the other contact 258a being connected to one of the contacts 264a and to the charger relay by conductor 323, the other contaot264a being connected to one of the contacts 259a by a conductor 324-. The circuit arrangement also includes a gun switch 192 adapted to be operated by the recoil movement of the gun carriage and a cyclic rate timer 254, the gun switch having a switch arm 193 and a pair of contacts 193a, one of the contacts 193a being connected to the lowerbarrel relay 262 by a conductor 325, the other contact 193a being connected to the other contact 259a of relay 256 and to the cyclic rate timer by a conductor 326, connected to conductor 320 and provided with a normally open firing switch 255, the timer being controlled by a switch 254a. It will be understood that by this arrangement the cyclic rate timer 254 may be connected in electrical parallel relationship with the firing switch 255, for controlling the rate of succeeding two round bursts of the gun. r

A gun charger (not shown) is employed to initiate the indexing action of the gun, the operation of which is set forth in the specification of the aforesaid copending application, SerialNo. 156,641, filed April 18,1950, now Patent No. 2,972,286, and illustrated in the drawings thereof, Figs.v 30, 34, and 35. As shown herein, the gun charger operating means includes a pair of gun chargor control solenoids 132, connected to one' of the contacts 261a of relay 260 by a conductor 327, the other contact 261a of relay 260 being connected to conductor 324 by conductor 328. V i

A pair of projector switches are provided in the circuit, indicatedgenerally at S1 and S2. Switch S1 comprises a firing pin'101 and a wiper shoe or contact 104, switch S2 comprises a firing pin 101 and a wiper shoe or contact 105, the aforesaid arrangement being adapted to fire primers or caps in the ammunition tubes 83 at the desired moment thereby to detonate the primers and propel the rounds R from ammunition tubes 83 and into the firing chambers in the rotary breech 50 as the rounds arrive at load position. A conductor 329 connects wiper shoe 104 to condenser 272 for conducting an electrical impulse to projectile switch S1 as the wiper shoe 104 engages firing pin 101 and condenser 272 is discharged therethrough. -A conductor 331 connects wiper shoe 105 to condenser 270 for conducting an electrical impulse to switch S2 as the wiper shoe 105 engages firing pin 101 and condenser270is discharged therethrough.

Upper and lower round firing devices generally indicated by the reference characters F1 and F2 are provided in the circuit and each include a firing pin 110, a conducting plate 124, a connector 116 and a spring arm 123. An electrical firing circuit to the firing device F1 is established by way of conductor plate 124, contacts 257a of upper barrel relay 256 and thence to condenser 266 by way of conductor 332, the electrical firing circuit to firing device F2 being established by way of conducting plate 124, contacts 263a of lower barrel relay 262 and thenceto condenser 268 by way of conductor 333. It will be understood that the above-mentioned several relays function in part to control application of the charges stored on condensers 266 and 268 to the two round firing pins whereupon the rounds in the breech chambers are fired and forceably ejected from gun barrels 40 and 41. Moreover, battery B operates motor 251 and the relays 256, 260 and 262 and the motor operates the generator 252, which stores a charge upon condensers 266, 268, 270 and 272 through resistors 265, 267, 269 and 271 in series therewith. Furthemtore, the power source B supplies power to operate thegun charger control solenoids 1 32,. as controlled by the action of the abovementioned relays. The gun switch 192 is adapted to be operated by the. recoil movement of the carriage and cooperates with the above-mentioned relays in controlling the. application of the charge: stored on condenser 268 to assure? 254, which is adapted to be connected in electrical parallel relationship 'with the firing switch 255 to provide means for controlling the rate of two round bursts of the rapid fire gun.

Referring again to the drawing it will be readily apparent that closure of ready switch 253 operates to energize the motor 251 from the power source 250 and to energize thecharger relay 260, causing its switch arm 261 to break from its contacts 261a. Energization of the motor 251 operates the generator 252 to charge the condensers 266, 268, 270, and 272. If at that moment two projector or ammunition carrying tubes 83 are in load position, as shown on the drawing the projector contact shoes 104 and 105 contact the projector firing pins 101 to fire the projector primers 85, loading these rounds into the firing chambers in alignment therewith and rotationally preceding the fire positions. It will be understood, however, that so long as ready switch 253 is maintained in closed position, rounds R brought into the closed with the ready switch 253 maintained in closed position, upper barrel relay 256 is immediately energized causing its switch arm 257 to engage contact points 25711, its switch arm 258 to break from contact points 258a, and its switch arm 259 to engage contact points 259a.

With the switcharms in this position, the charged condenser 266 would fire a round from the upper barrel 40 if one were there in fireposition, But since that firing chamber is empty, that circuit remains open; ,The breaking of switch arm 258 from its contact points 258a de' energizes the charger relayj26il, but this relay being designed to return to normally biased position with its switch arm in engagemet with contact points 261a after a short time delay, the circuit to the gun charger control solenoids 132, which would otherwisebe closed by the closure of switch arm 259 to its'contacts 259a, remains open. However, after the lapse of the time interval required for, relay switch arm 261 to return to its normally biasedposition in engagement with thecontacts 261a, the gun charger control solenoids are energized, causing the. operation of the charger mechanisms (not shown) to drive the carriage (not shown) through :a recoil and counterrecoil cycle.

As the carriage approaches the rearward limit of recoil .travel the gun switch 192 is closed thereby, which immediately results in energization of the lower barrel relay 262 causing its switch arms 263 and 264to engage their-respective contact points 2634 and 264a. The closure of switch arm 263 would fire a round in alignment with the lower barrel 41 by connecting the condenser v 268 thereto through the lower barrel firing pin 110, but

no round is as yet positioned there.

With'switch arm 259 of upper barrel relay 256 held closed to its contacts, the closure of the switch arm 264 of the lower barrel relay 262 operates to reenergize the charger relay 260, again breaking its switch arm 261 from its contacts 261a to deenergize the charger solenoids 132.

The switch arm 261 is held in open position so long as switch arm 264 and switch arm 259 are held closed to 7 their respective contacts. rearward limit of recoil travel and starts forward in a After the carriage passes the counterrecoil motion the gun switch is opened, but lower .barrel relay 262, being designed for a time delay in its return to normally biased position, remains in its coil energized 'position with its switch arms 263 and 264 closed to their respective contact points.

Thus, when the carriage approaches battery position iround is aligned with each of the two gun barrels and "both are immediately fired by the charges carried on the condensers 266 and 268, connected to the rounds through switch arms 257 and 263, respectively. The time delay return action of lower barrel relay 262 and charger re- 1ay'260 are such as to maintain the relays in energized position after deenergization of their coils for a period of time exceeding the time required for one indexing cycle of ,the gun.

Thus, upon the firing of the two rounds above-mentioned, the recoil force of one of these rounds counteracts thecounterrecoil force resulting from operation of the charger mechanisms, while the recoil force of the other round operates to drive the carriage into another indexing cycle with the recoil force of one round. Since the gun switch is closed on each recoil action to energize the coil of the lower barrel relay 262, so long as the firing switch 255 and ready switch 253 are held closed the roundsare continuously loaded into the firing chambers of the breech and pairs of the rounds are simultaneously and automatically fired from the gun, the switch arms of the barrel relays 256 and 262 being continuously held in energized position.

net re coil energy to drive the carriage into recoil position 1 recoil action of this round closes the gun switch during resulting from the previous firing of a pair of rounds from the gun, since the switch arms 263. and 264 of delayed action relay 262-are held closed to their contact points during this time despite the opening of the firing switch,

7 the round aligned with the lower barrel 41 as a result of the last indexing cycle is fired, providing a recoil impulseof one round to counteract the counterrecoil energy of the previous firing and to bring the operation of the carriage to a halt, there being substantiallyno resultant as had previously resulted from the-second round of each pair fired.

I The gun now-in the condition of having a single round 40 aligned with'its' upper barrel and a fired cartridge case aligned with its lower barrel, a subsequent closure of the firing switch 255 energizes the upper barrel relay 256 and results in an immediate firing of the round aligned with the upper barrel to drive the carriage into a recoil and counterrecoil cycle with the impulse of a single round. The

recoil travel of the carriage to energize the lower barre relay 262 and thus permits the gun to continue firing in the manner above-described. The charger relay switch arm 261 is held away from its contact points 261a du"- ing'this entire burst.

In the event that during a burst two dud rounds or'two misfires should simultaneously occur, there being no cycleon its return therefrom. Since the firing switch is maintained closed and since the gun switch again closes 'at the 'end of rearward recoil travel of the carriage, the

gun continues to operate and two new rounds are aligned withthe'two barrels, which are 'fired during the return of the carriage to battery position, the three relays being thus held in their normal operating position. Therefore no interruption occurs in the operation of the gun.

If, however, during a burst, one of the two rounds aligned with the barrels fails to fire, the firing of the single round counteracts the counterrecoil energy and brings the operation of the gun to a halt. However, if the firing switch 255 is continuedto be held in closed position; the lower barrel relay 262 and ,hence the charger relay 260 shortly return to their normally biased position, causingthe'gun 7 charger control solenoids to be energized and resulting in an indexing action under the operation of the charger mechanisms. The result thereof is' the same as the above-described initial operation of the gun, the switch arms ofthelower barrel relay 262 being closed and the charger relay switch arm 261 being therefore broken from its contacts 251a upon the carriage reaching the.

limit of rearward recoil travel, enabling continued ahtomatic operation of the gun.

When the gun is operated through the firing switch 255, it is apparent that the rate of fire is controlled solely by the rate of mechanical cycling of the carriage. When a lesser rate of fire is desired, the firing switch is left open and the present circuit is closed through the cyclic rate timer 254 and its control switch 254a, which provide for opening and closing of the present circuit at a desired adjustable rate. As will be apparent to those skilled inthe art, with each closure of the circuitby the, cyclic rate timer the round loader in alignment with the upper barrel 40 is immediately fired to cause an indexing action of the gun, and the circuit is automatically opened after closure of the gun switch 192. The return of the carriage toward battery position results in firing that round brought into alignment with the lower barrel 41 :to bring the indexing action of the gun to a halt. Such successive pairs of firing may be accomplished at any desired rate in accordance with the setting of the cyclic rate timer up to the maximum rate of automatic fire as would b obtained by closure of the firing switch 255.

In the event that during controlled cyclic rateoperation of the present gun a dud round or two dud'rounds should be placed in firingposition, the results thereof will be apparent from a consideration of the circuit as described in detail above with reference to full automatic firing through the closure of the firing switch 255. Such dud or duds may becleared from the gun and normal operationthereof resumed by switching from cyclic rate controlled operation to full automatic fire; or if desired,

means maybe provided to cooperate with the cyclic rate timer 254 in conjunction with the operating portions of the remainder of the circuit and gun so that such normal operation may be resumed under continued control of the cyclic rate timer, as would be apparent to one skilled in the art.

At this point it should be readily apparent that the present circuit provides the feature of hang-fire proof construction under all conditions of operation. If after the firing of a burst a second burst is attempted, the round in alignment with the upper barrel is delayed in firing, because of the delay in operation of the charger relay the charger mechanisms do not initiate an indexing cycle until a sufiicient time interval has elapsed to permit the hang-fire to be propelled. Thus, it is insured that the hang-fire fires while that round remains aligned with a barrel. Also, if during a firing burst one hang-fire becomes aligned with a barrel in firing position and the other round fires normally, the reciprocation of the carriage is thereby stopped, but because of the delay in operation of the charger relay a sufficient time interval is provided to enable the hang-fire to be ignited before a charger operated indexing cycle is initiated. Further, if

during a firing burst two hang-fires arealignedwith the barrels in firing position, the time interval provided by the, carriage sliding forward past battery position into bufiing" and its rearward return through battery toward recoil position is suficient to enable the hang-fire to be ignited before the next indexing cycle is started.

In the normal operation of the present circuit, that is in the absence of any dud rounds or misfires and under full speed operation thereof, as effected by the closure of the firing switch 255 rather than under the control of the cyclic rate timer 254, the operation is briefly as follows: Closure of the ready switch 253 results in the loading of two rounds then in the load position into the firing chambers, placing the gun in readiness for firing. Subsewith the upperbarrel. switch. results in firing the round left in alignment with quent closure of the firing switch 255. results ingcharging of the gun by means of the charger solenoids which operates the charger mechanism, to actuate the carriage, barrels, and rotatable .breech through one indexing cycle with the impulse equivalent to the firing ofa single ,round. The two rounds loadedare thusindexed into alignment with the two barrels of the gun, and shortly before the carriage returnsto battery position these rounds are fired. g

Meanwhile two new rounds have been loaded in the next rotationally succeeding firing chambers which are indexed into alignment with the barrels and fired as a result of the indexing cycle following the previous firing. The feeding of rounds carried by the projectors is continued in synchronism with the rotation of the breech, and the loading of rounds into the firing chambers and the firing of those so loaded is automatically continued so long as the firingswitch 255 is held closed.

Upon the opening of the firing switch, the next time the carriage approaches battery position the round allgned with the'lower barrel is alone fired to stop the indexing action of thegun, leaving a live, round in alignment Subsequent closure of the firing firing of the rounds.

Obviously many, modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. An electrical firing and operational control systern for a two barrel .gun comprising a 1 gun charger solenoid including an operating circuit therefore, a relay included in said charger, solenoid circuit, a normally open first barrel firing circuit, a normally open second barrel firing circuit, a relay included in said first barrel firing circuit, contact elements in said first barrel firing circuit, a contact controlled by said relay in the first barrel firing circuit and movable into engagement with said. contact elements in the first barrel firing circuit as said relay therein is energized for closing said firing circuit, means including a source of electrical energy for energizing said relay in the first firingci rcuit, a relay included in said second barrel firing circuit, contact elements in said second barrel firing circuit, a contact controlled by said relay in the second barrel firing circuit and movable into engagement witlrsaid contact elements in responsive to the recoil action of the gun and operatively connectedto the relay of said second barrel circuit for causing energization of the relay in the second barrel .firing circuit, a normally charged condenser included in the second firing circuit for rendering the second firing circuit effective as the contact of the second firing circuit is moved into engagement with the contact elements of said second firing circuit, additional contact means movable by the relay in said first firing circuit into engagement with complementary means connected to the relay of said charger circuit as the relay in the first firing circuit is energized for causing de-energization of the relay in the charger circuit, a switch device controlled by the relay in said charger circuit, complementary means 9 included in said charger circuit and engageable by said switch device for closing the charger circuit as the relay therein is de-energized, and means connected to said switch device for moving said switch device into engagement with said complementary means in the charger circuit as the relay of the charger circuit is de-energized.

2. A system according to claim 1 and including a first primer firing circuit, normally open first switch means included in said first primer circuit and actuated to a closed position by the action of the gun for closing said first primer circuit, a normally charged condenser included in said first primer circuit for rendering the first primer circuit effective as said first switch means therein is actuated to said closed position, a second primer firing circuit, normally open second switch means included in said second primer circuit and actuated to a closed position by the action of the gun for closing the second primer circuit, a normally charged condenser included in said second primer circuit for rendering the second primer circuit efiective as said switch means therein is actuated to a closed position, and means including a source of electrical energy connected to said condensers for applying an electrical charge on the condensers.

3. An electrical firing and operational control circuit for a twin barrel gun comprising a gun charger solenoid including a normally closed operating circuit therefor, a normally open first barrel firing circuit, contact elements included in said first firing circuit, a relay in said first firing circuit, switch means operatively connected to said relay in said first firing circuit and movable into engagement with said contact elements upon energization of said relay for closing said first firing circuit, a normally charged electrical energy storage device connected to said contact elements in said first firing circuit for rendering said first firing circuit effective as said switch circuit, a normally charged electrical energy storage de-- vice connected to said second contact elements of the second firing circuit for rendering the second firing circuit effective as said second switch means moves into engagerelays, means including a switch element on said first rclay and normally connected to the relay of the operating circuit for causing energization of the charger relay, a switch device operatively connected to said charger relay and normally in engagement with complementary means in said charger circuit and movable out of'engagement with said complementary means in response to the energization of said charger relay for opening said normally closed operating circuit, and spring means connected to said switch device for returning said switch device into engagement with said complementary means to close the operating circuit upon de-energization of the charger relay.

4. An electrical firing and operational control circuit for a two barrel gun comprising a gun charger solenoid, an operating circuit for said gun charger solenoid, a first barrel firing circuit, a second barrel firing circuit, a relay included in said first barrel firing circuit, means including a first switch device actuated by the relay in said first barrel for closing the first barrel firing circuit, a relay included in said operating circuit, contact elements included in said operating circuit, switch means controlled by said relay in the operating circuit and normallyin engagement with said contact elements for closing the operating circuit of the'charger solenoid, spring means connected to said switch means for maintaining the switch means in engagement with said contact elements untilsaid relay in said operating circuit is actuated, said switch means being movable out of engagement with said contact elements as the relay in the operating circuit is actuated to open the operating circuit to the charger solenoid, means including a gun switch connected to-the second barrel relay and responsive to the recoil action of the gun for actuating the relay in the second barrel firing circuit,

means including a second switch device actuated by the I relay in said second barrel circuit for closing the second firing circuit, a normally charged condenser included in ment with the contact elements of the second firing cirsaid first firing circuit for rendering the first firing circuit effective as the first firing circuit is closed by said first switch device, .and a normally charged condenser included in the second firing circuit for rendering the sec ond firing circuit effective as the second firing circuit is closed by the second switch device.

' References Cited in the file of this patent V UNITED STATES PATENTS 

